.TH std::list 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::list \- std::list

.SH Synopsis
   Defined in header <list>
   template<

       class T,                                                       \fB(1)\fP
       class Allocator = std::allocator<T>

   > class list;
   namespace pmr {

       template< class T >                                            \fB(2)\fP \fI(since C++17)\fP
       using list = std::list<T, std::pmr::polymorphic_allocator<T>>;

   }

   std::list is a container that supports constant time insertion and removal of
   elements from anywhere in the container. Fast random access is not supported. It is
   usually implemented as a doubly-linked list. Compared to std::forward_list this
   container provides bidirectional iteration capability while being less space
   efficient.

   Adding, removing and moving the elements within the list or across several lists
   does not invalidate the iterators or references. An iterator is invalidated only
   when the corresponding element is deleted.

   std::list meets the requirements of Container, AllocatorAwareContainer,
   SequenceContainer and ReversibleContainer.

.SH Template parameters

               The type of the elements.

               T must meet the requirements of CopyConstructible. T must meet the (until
               requirements of CopyAssignable if list::operator= or list::assign  C++11)
               is instantiated with T.
               The requirements that are imposed on the elements depend on the    (since
               actual operations performed on the container. Generally, it is     C++11)
               required that element type is a complete type and meets the        (until
               requirements of Erasable, but many member functions impose         C++17)
               stricter requirements.
               The requirements that are imposed on the elements depend on the
               actual operations performed on the container. Generally, it is
   T         - required that element type meets the requirements of Erasable, but
               many member functions impose stricter requirements. This container
               (but not its members) can be instantiated with an incomplete
               element type if the allocator satisfies the allocator completeness (since
               requirements.                                                      C++17)

                         Feature-test macro             Value    Std    Feature
                                                                       Minimal
               __cpp_lib_incomplete_container_elements 201505L \fI(C++17)\fP incomplete
                                                                       type
                                                                       support


               An allocator that is used to acquire/release memory and to
               construct/destroy the elements in that memory. The type must meet the
               requirements of Allocator.
   Allocator - The behavior is undefined
               \fI(until C++20)\fP
               The program is ill-formed
               \fI(since C++20)\fP if Allocator::value_type is not the same as T.

.SH Member types

   Member type            Definition
   value_type             T
   allocator_type         Allocator
   size_type              Unsigned integer type (usually std::size_t)
   difference_type        Signed integer type (usually std::ptrdiff_t)
   reference              value_type&
   const_reference        const value_type&
                          Allocator::pointer                        \fI(until C++11)\fP
   pointer                std::allocator_traits<Allocator>::pointer \fI(since C++11)\fP


                          Allocator::const_pointer                        \fI(until C++11)\fP
   const_pointer          std::allocator_traits<Allocator>::const_pointer \fI(since C++11)\fP


   iterator               LegacyBidirectionalIterator to value_type
   const_iterator         LegacyBidirectionalIterator to const value_type
   reverse_iterator       std::reverse_iterator<iterator>
   const_reverse_iterator std::reverse_iterator<const_iterator>

.SH Member functions

   constructor   constructs the list
                 \fI(public member function)\fP
   destructor    destructs the list
                 \fI(public member function)\fP
   operator=     assigns values to the container
                 \fI(public member function)\fP
   assign        assigns values to the container
                 \fI(public member function)\fP
   assign_range  assigns a range of values to the container
   (C++23)       \fI(public member function)\fP
   get_allocator returns the associated allocator
                 \fI(public member function)\fP
.SH Element access
   front         access the first element
                 \fI(public member function)\fP
   back          access the last element
                 \fI(public member function)\fP
.SH Iterators
   begin         returns an iterator to the beginning
   cbegin        \fI(public member function)\fP
   \fI(C++11)\fP
   end           returns an iterator to the end
   cend          \fI(public member function)\fP
   \fI(C++11)\fP
   rbegin        returns a reverse iterator to the beginning
   crbegin       \fI(public member function)\fP
   \fI(C++11)\fP
   rend          returns a reverse iterator to the end
   crend         \fI(public member function)\fP
   \fI(C++11)\fP
.SH Capacity
   empty         checks whether the container is empty
                 \fI(public member function)\fP
   size          returns the number of elements
                 \fI(public member function)\fP
   max_size      returns the maximum possible number of elements
                 \fI(public member function)\fP
.SH Modifiers
   clear         clears the contents
                 \fI(public member function)\fP
   insert        inserts elements
                 \fI(public member function)\fP
   insert_range  inserts a range of elements
   (C++23)       \fI(public member function)\fP
   emplace       constructs element in-place
   \fI(C++11)\fP       \fI(public member function)\fP
   erase         erases elements
                 \fI(public member function)\fP
   push_back     adds an element to the end
                 \fI(public member function)\fP
   emplace_back  constructs an element in-place at the end
   \fI(C++11)\fP       \fI(public member function)\fP
   append_range  adds a range of elements to the end
   (C++23)       \fI(public member function)\fP
   pop_back      removes the last element
                 \fI(public member function)\fP
   push_front    inserts an element to the beginning
                 \fI(public member function)\fP
   emplace_front constructs an element in-place at the beginning
   \fI(C++11)\fP       \fI(public member function)\fP
   prepend_range adds a range of elements to the beginning
   (C++23)       \fI(public member function)\fP
   pop_front     removes the first element
                 \fI(public member function)\fP
   resize        changes the number of elements stored
                 \fI(public member function)\fP
   swap          swaps the contents
                 \fI(public member function)\fP
.SH Operations
   merge         merges two sorted lists
                 \fI(public member function)\fP
   splice        moves elements from another list
                 \fI(public member function)\fP
   remove        removes elements satisfying specific criteria
   remove_if     \fI(public member function)\fP
   reverse       reverses the order of the elements
                 \fI(public member function)\fP
   unique        removes consecutive duplicate elements
                 \fI(public member function)\fP
   sort          sorts the elements
                 \fI(public member function)\fP

.SH Non-member functions

   operator==
   operator!=
   operator<
   operator<=
   operator>
   operator>=           lexicographically compares the values of two lists
   operator<=>          \fI(function template)\fP
   (removed in C++20)
   (removed in C++20)
   (removed in C++20)
   (removed in C++20)
   (removed in C++20)
   (C++20)
   std::swap(std::list) specializes the std::swap algorithm
                        \fI(function template)\fP
   erase(std::list)     erases all elements satisfying specific criteria
   erase_if(std::list)  \fI(function template)\fP
   (C++20)

     Deduction guides \fI(since C++17)\fP

.SH Notes

       Feature-test macro       Value    Std                   Feature
   __cpp_lib_containers_ranges 202202L (C++23) Ranges construction and insertion for
                                               containers

.SH Example


// Run this code

 #include <algorithm>
 #include <iostream>
 #include <list>

 int main()
 {
     // Create a list containing integers
     std::list<int> l = {7, 5, 16, 8};

     // Add an integer to the front of the list
     l.push_front(25);
     // Add an integer to the back of the list
     l.push_back(13);

     // Insert an integer before 16 by searching
     auto it = std::find(l.begin(), l.end(), 16);
     if (it != l.end())
         l.insert(it, 42);

     // Print out the list
     std::cout << "l = { ";
     for (int n : l)
         std::cout << n << ", ";
     std::cout << "};\\n";
 }

.SH Output:

 l = { 25, 7, 5, 42, 16, 8, 13, };

   Defect reports

   The following behavior-changing defect reports were applied retroactively to
   previously published C++ standards.

     DR    Applied to        Behavior as published              Correct behavior
                      T was not required to be
   LWG 230 C++98      CopyConstructible                   T is also required to
                      (an element of type T might not be  be CopyConstructible
                      able to be constructed)
   LWG 276 C++98      T was always required to be         only required if operator= or
                      CopyAssignable                      assign is instantiated with T
